Why do different temperatures produce different growth rates?
Because different type of bacteria require different temperature range to grow.
Optimum temperature
Temperature that bacteria growth is fastest
Minimum temperature
the lowest temperature that bacteria can survive
Maximum temperature
the highest temperature that bacteria can survive
Turbidity
Cloudiness of culture that is use in measure bacteria growth after exposed to certain temperature.
Spectrophotometer
A device that measure bacteria growth after being expose to certain temperature in response absorbance of light by the culture turbidity
Optical density
The higher the cells growth the higher the light will be absorbed in the culture
Psychrophiles
Organism that live in temperature below 20oC
Psychrotrophs
Organism that prefer cold temperature but can survive in temperature around 35oCThey more likely to cause infectious diseases because their optimum temperature is between 15o C - 30o C
Mesophiles
Organism that live in medium range temperature
From 15oC - 20oC to 37oC - 45oC
Thermophiles
Heat loving organism
Above 45oC to 80oC
Extreme thermophiles
Organism that live in temperature between 80oC - 110oC
Thermoduric
Organism that like medium heat but can survive temperature up to 110oC
Osmosis
Diffusion/movement of water
Water activity
Osmotic pressure
What is hypertonic? What happens as result of it?
More solutes in the environment then inside the cell
H2O will diffuse out of the cell
What is hypotonic? What happens as result of it?
Less solutes in the environment then inside the cell.
Water will defuse inside the cell
What is isotonic? What happens as result of it?
The solute amount is equal in the environment and inside the cell
No H2O movement
Plasmolysis
The cell will shrink and its membrane will pull away from its cell wall due to loss of water in hypertonic environment
What salinity % range can non tolerant bacteria can survive in?
3% - 5%
Halotolerant
Bacteria that can survive and grow in up to 11% salinity environment
Halophiles
Salt loving organism
NaCl 15% - 30%
Osmophiles
Sugar loving organism
Visible radiation
Microwaves & radio waves
Ionizing radiation
Gamma ray & X ray
Non-ionizing radiation
UV light
Pyrimidine dimers
Damage to DNA caused by UV radiation that form covalent bonds between adjacent pyrimidines and cause kinks in the DNA.
What are the variables we used in the UV radiation experiment?
Time of exposure
barrier present/absent
Distance from light source
Wavelength we used 260 nm
What are the standardized we used in the UV radiation experiment?
Distance
wavelength 260 nm
strict aerobes
Organism that require O2 to make ATP (survive)
strict anaerobes
Organism that will die as result of exposure to O2
Facultative anaerobes
Organism that will use O2 to grow if it available but if there is no O2, They will use other method to make ATP.
Aerotolerants
Organism that will not use O2 but will not die from it.
Microaerophilic
Organism that require O2 in just the right amount.
Too much or too little O2 will kill them.
What property does Bacillus megaterium have that staphylococcus aureus does not have that allow it to survive longer exposure to UV light?
How does it work?
Endospore
Bound with acid soluble proteins that give it better protection from UV light